Dinking around with 71 Demons and Dusters I have seen too many variables to make the call on what is correct or not and could use some input from you guys.

In 1971 you got:

Manual drum brakes (standard)
Manual (front) disc brakes
Power drum brakes
Power (front) disc brakes

I've seen 3 basic styles of master cylinders used (looking at what APPEAR to be original cars) some appear to be the wrong ones based on the information I can find.

What I am trying to determine is which style would be correct for a 71 with manual disc brakes. The pictures I'm posting are examples I have seen so far. First up are a survivor 1971 Demon and a survivor 1972 Duster both equipped with power brakes (I believe both also have front discs, I will verify and post later). Notice how the front of one MC is flat while the other is rounded.